Peters will be eligible for parole in August 2021 for the crime - a non-parole period of 10 years.

On August 3 last year, Peters, 50, wearing a bright, rainbow-coloured balaclava, walked into the $12 million Mosman home of 18-year-old Madeleine Pulver and tied a black metal box around her neck with a bike chain.

Attached was an extortion note claiming the box contained sophisticated plastic explosives and threatening Ms Pulver and her family with a "tragically avoidable explosion" if they failed to send "funds" to a supplied email address.

It took 10 hours for police to be certain the device was a fake, by which time Ms Pulver had been traumatised.

Over the coming days, state and federal police launched a major investigation that ultimately led them to Louisville, Kentucky, where Peters was arrested on August 15.

After initially denying any involvement with the crime, Peters pleaded guilty to aggravated break and enter and detaining for advantage in March this year, much to the relief of his teenage victim and her parents, Bill and Belinda Pulver.

It emerged that Peters had become obsessed with a science fiction book he was writing - a dark dystopia that included among its pages the kidnapping of a young girl by a black-hearted protagonist.

During three recent sentencing hearings, Peters's lawyers argued that, affected by bi-polar disorder, alcoholism and depression brought on by the loss of his job and his marriage, he had committed the crime under the delusion that he was the central character in his novel.

But the prosecution painted a very different picture.

Crown Prosecutor Margaret Cunneen, SC, said Peters had been angry at losing his wealth and status and had decided "get it all back in one go".

She said the 52-year-old had come to Sydney from his home in the USA intending to extort money from the beneficiary of a large trust fund - the James M Cox trust.

He had abandoned this target when he stumbled across a prominent Sydney businessman who lived on the same battle-axe block as the Pulvers.

Bizarrely, according to the Crown, it was a simple mistake which led Peters to the Pulvers's door — he had mistaken the Pulvers's house for that of his intended target.

The court previously heard that the standard non-parole period for the type of crime Peters committed was five years, though prosecutors argued that his was in the most serious category of this offence.

Having pleaded guilty early on, Peters received a 25 per cent discount on his sentence.